Electric transformer



April 19, 1932. G S

I ELECTRIC TRANSFORMER Filed March 1, 1950 WW o /mfl u 4 p M m/ .l 1. A d! 2 1 1III|IIII||IHIIP 0, m m 4 fi m 5 Patented Apr. 19, 1932 UNI ED STATES PATENT orrlcr.

I JOSEPH G. SOLA, OI CHICAGO, ILLINOIS, ASSIGNOB TO SOLA CORPORATION, OF CHICAGO,

., ILLINOIS, A CORPORATION OF ILLINOIS ELECTRIC TRANSFORMER This invention relates to an electric transformer, preferably of the constant current type adapted for use in connection with the illumination of gaseous tube signs and in other installations wherever a constant current t pe of transformer may be suitable.

An ob ect of the invention is the'p'rovision of an improved form and arrangement of parts in a transformer of'the balanced type so constructed that as each impulse of alternating current builds up in the primary coil with the secondary coil closed through a neon tube the magnetic flux threads initially through both the primary and the secondary coils, and that 1 when the counter magnetic flux pressure reaches a predetermined maximum 5. portion of the magnetic flux is diverted across an airgap in a shunt return path, whereby the voltage of the current flowing through the sec- 2 ondary coil is cut down. It is one of my objects to provide an arrangement of this type in which-the primary and secondary coils are closely coupled so as to'have high efficiency for building up the initial high voltage in the secondary coil. To this end, it has been one of my objects to provide an improved arrangement by which a shunt return path bypassing the secondary, coils can be provided without the necessity for interposing the core parts for such shunt return path between the ends of the primary and secondary coils.

Other objects will appear hereinafter.

The invention consists in the combinations and arrangements of parts hereinafter described and claimed. The invention-willbe bestunderstood by reference to the accompanying drawings forming a part of thisspecification, and in which:

Fig. 1 is a diagrammatic illustration of the preferred embodiment of the invention; and

Fig. 2 is a side elevational view of the transformer proper.

As illustrated, the preferred embodiment comprises a core member having an intermediate portion 9 of greater width than that of its end portions 7 and 8, in the constructionshownthe widened portion of such core member being formed integrally with the memberin the form of a lug projecting trans a lication filed March i, 1930. Serial no. 432,332.

versely from one side of the member. The

on the narrower end portions 7 and 8 of the core member with their inner ends opposite the ends of the primary coil 12 and in close proximity thereto so as to have close coupling therewith. The secondary coils are connected at their inner ends by leads 19 and 20, said coils being mounted and connected so that one coil serves as a continuation of the other coil, as is clearly shown in Fig; 1. The connected coils are provided with output leads 17 and 18 for connection with .a neon tube or other load device as may be desired. 7

1n the arrangement shown, an all metal magnetic return path is provided for the magnetic flux threading the primary coil 12 and the secondary coils 13 and 14, such return path being in the form of a core memher 4 in the form of a yoke which engages the ends of the core member comprising the parts 7, 9 and 8, in the arrangement shown such yoke member 4 being formed integrally with the core member comprising said parts 7, 9 and 8. Other core members 10 and 11 are also provided, connected at their outer ends with the outer ends of the core member 798,

and projecting at their inner ends into the desired effective relationship to the opposite ends of'the widened core portion 9 upon which the primary coil 12 is mounted. As is clearly shown in Fig. 1, the ends of the core members 10 and 11 are separated by air gaps from the ends of the core portion 9, thus providing the desired impedance with respect to the flow of magnetic flux therethrough. As will be readily appreciated, the core members 10 and 11 constitute shunt paths serving to by-pass the secondary coils 13 and- 14. In the arrangement shown in Fig. 1, the leads 19 and 20 are shown as being grounded to the core. In the construction shown, all of the core parts are of laminated formation.

In the use of my improved arrangement, the current delivered by the secondary coils is arbitrarily limited, being controlled by a regulation of the size of the air gaps at the ends of the shunt core members 10 and 11- As an impulse of alternating current builds up in the primary coil, with the secondary coils connected with a neon tube lamp, an induced current is at the same time built up in the secondary coils, my arrangement being very effective for buildingup such induced current by reason of the close coupling of the secondary coils with the primary coil. lhis induced current develops a counter magnetic flux pressure resisting the flow of the magnetic flux through the core member T98, which soon reaches such proportions as to equal the break-down resistance of the air gaps with respect to the fiow of magnetic fiux thereacross in the shunt return paths. As soon as the air gap resistance has been broken down, a greatly increased flow of the magnetic flux through the shunt path takes place serving to lay-pass the secondary coils, with the result that there is asharp drop in the voltage of the induced current flowing through the secondary coils. This serves also to limit the current flowing through the secondary coils, the maximum current permitted to flow being that required for establishing the leakage flow of magnetic flux through the shunt paths across the air gaps.

By the provision of my improved arrangement in which the initial high voltage in the secondary coils is built up promptly by cilicieut operation due to the close coupling of the coils, great brilhancy of operation of the tube is attained without the use of an excessively high voltage.

ld hile I have illustrated and described the preferred form of construction for carrying my invention into effect, this is capable of variation and modification without departfrom the spirit of the invention. I,

therefore,.do not wish to be limited to the precise details of construction set forth, but desire to avail myself of such variations and modifications as come within the scope of the appended claims.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent is:

1. A transformer comprising in combination a core member of greater width at one point than at another point, a coil mounted on the wider portion of said core member, a second coil mounted on the narrower portion of said core member at the end of said first named coil, a second core member providing a second coil from the narrower end of said 2. A transformer comprising in combination a core member of greater width at an intermediate point than at its ends, a primary.

coil mounted on the wider portion of said core member, secondary coils mounted on the na rrower end portions of said core member at opposite ends of said first named coil, a second core member providing a metal return path for the magnetic flux threading said three coils through said first named core member, and other core members providing shunt return paths around said secondary coils respectively each from one end of said first named core member to the adjacent end of the wider portion of said first named core memher and each including an air gap in the shunt return path provided thereby.

3. A transformer comprising in combination a core member of greater idth at an intermediate point than at its ends, a primary coil mounted on the Wider portion of said core member, secondary coils mounted on the narrower portions of said core member at opposite ends of said first named coil and in closely coupled relationship thereto, a second core member providing a metal return path for the magnetic flux threading said three coils through said first named core member, and other core members providing shunt return paths around said secondary coils respectively each from one end of said first named core member to the adjacent end of the wider portion of said first named coremember and each including an air gap in the shunt return path provided thereby.

i. A transformer comprising in combination a core member of greater width at an intermediate point than at its ends, a primary coil mounted on the wider portion oi said core member, balanced secondary coils mounted A on the narrower portions of said core member at opposite ends of said first named coil and in closely coupled relationship thereto, a second core member providing a metal return path for the magnetic flux threading said 35 named core member to the adjacent end of the wider portion of said first named core member, said shunt return paths including air gaps having equal and similar impedance effects with respect to the leakage flux flowing therethrough.

In testimony whereof I have signed my name to this specification.

JOSEPH G. SOLA. 

